From: Eric Dumazet <eric.dumazet@gmail•com>
To: Sowmini Varadhan <sowmini.varadhan@oracle•com>
Cc: Willem de Bruijn <willemdebruijn.kernel@gmail•com>,
Network Development <netdev@vger•kernel.org>,
David Miller <davem@davemloft•net>,
rds-devel@oss•oracle.com, santosh.shilimkar@oracle•com
Subject: Re: [PATCH RFC net-next 1/6] sock: MSG_PEEK support for sk_error_queue
Date: Thu, 18 Jan 2018 08:53:15 -0800 [thread overview]
Message-ID: <1516294395.3606.23.camel@gmail.com> (raw)
In-Reply-To: <20180118161048.GB24553@oracle.com>
On Thu, 2018-01-18 at 11:10 -0500, Sowmini Varadhan wrote:
> On (01/18/18 07:54), Eric Dumazet wrote:
> >
> > Some applications out there would break horribly, trust me.
> >
>
> so I'm not particularly attached to that solution, and I appreciate
> the wisdom (and the NACK), but lets try to find a useful alternative
>
> The current zcopy completion notification mechanism involves syscall
> overhead already, and is also inadequate for threaded applications sharing
> an fd. Plus it wont work for datagram sockets.
>
> I'm fine with Willem's suggestion of passing a fixed number of cookies
> as ancillary data (with CTRUNC to denote inadequate buffer) but if we
> are really so thrifty about syscall overhead, we should not be using
> sk_error_queue in the first place- perhaps we can pass up the completion
> notification as ancillary data with recvmsg() on the POLLIN channel
> itself (which is weird if there is no data to recv, and only ancillary
> info to pass up, but hey, we are "performant"!).
The thing is : MSG_PEEK 'support' will also need SO_PEEK_OFF support.
And begins the crazy stuff.
So lets properly design things, and not re-use legacy stuff that is
proven to be not multi-thread ready and too complex.
If you want to design a new channel of communication, do it, and
maintain it.
next prev parent reply other threads:[~2018-01-18 16:53 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-17 12:19 [PATCH RFC net-next 0/6] rds: zerocopy support Sowmini Varadhan
2018-01-17 12:19 ` [PATCH RFC net-next 1/6] sock: MSG_PEEK support for sk_error_queue Sowmini Varadhan
2018-01-17 23:50 ` Willem de Bruijn
2018-01-18 11:02 ` Sowmini Varadhan
2018-01-18 15:54 ` Eric Dumazet
2018-01-18 16:10 ` Sowmini Varadhan
2018-01-18 16:53 ` Eric Dumazet [this message]
2018-01-18 17:12 ` Sowmini Varadhan
2018-01-18 22:54 ` Willem de Bruijn
2018-01-18 23:03 ` Sowmini Varadhan
2018-01-18 23:09 ` Willem de Bruijn
2018-01-18 23:20 ` Sowmini Varadhan
2018-01-18 23:24 ` Willem de Bruijn
2018-01-18 15:51 ` Eric Dumazet
2018-01-17 12:20 ` [PATCH RFC net-next 2/6] skbuff: export mm_[un]account_pinned_pages for other modules Sowmini Varadhan
2018-01-17 12:20 ` [PATCH RFC net-next 3/6] rds: hold a sock ref from rds_message to the rds_sock Sowmini Varadhan
2018-01-17 12:20 ` [PATCH RFC net-next 4/6] sock: permit SO_ZEROCOPY on PF_RDS socket Sowmini Varadhan
2018-01-18 0:03 ` Willem de Bruijn
2018-01-17 12:20 ` [PATCH RFC net-next 5/6] rds: support for zcopy completion notification Sowmini Varadhan
2018-01-18 0:23 ` Willem de Bruijn
2018-01-18 11:40 ` Sowmini Varadhan
2018-01-18 22:46 ` Willem de Bruijn
2018-01-17 12:20 ` [PATCH RFC net-next 6/6] rds: zerocopy Tx support Sowmini Varadhan
2018-01-18 0:32 ` Willem de Bruijn
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1516294395.3606.23.camel@gmail.com \
--to=eric.dumazet@gmail$(echo .)com \
--cc=davem@davemloft$(echo .)net \
--cc=netdev@vger$(echo .)kernel.org \
--cc=rds-devel@oss$(echo .)oracle.com \
--cc=santosh.shilimkar@oracle$(echo .)com \
--cc=sowmini.varadhan@oracle$(echo .)com \
--cc=willemdebruijn.kernel@gmail$(echo .)com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox